Synthesis Of Magnetic Fe₃O₄@Pd Janus Nanoparticles For Multi-modality Imaging Guided Combined Therapy For Breast Cancer

Fe₃O₄/Pd magnetic Janus nanoparticles can combine magnetic nanomaterials with palladium nanosheets to provide a variety of functions and advantages,such as disease diagnosis and treatment,it can be used for disease multi-mode accurate diagnosis,treatment and real-time disease Evaluation and other aspects,and thus have broad clinical application prospects.However,at present,Janus nanoparticles still have problems in preparation method and limited application.This paper firstly proposes a simple and convenient method for preparing magnetic Janus nanoparticles,which is used for multi-modal imaging-mediated magneto-optical heat.The specific research work is as follows:(1)Synthesis and characterization of Fe₃O₄/Pd magnetic Janus nanoparticles.Firstly,15 nm oil phase iron oxide nanoparticles and 13 nm two-dimensional palladium nanosheets were prepared by high temperature thermal decomposition and wet chemical methods respectively,and then dopamine was modified on the surface of iron oxide by ligand exchange,not only to realize magnetic iron oxide nanoparticles.The aqueous phase is transferred and the surface of the particles is positively charged.The iron oxide nanoparticles and the two-dimensional palladium nanosheets with negative charge on the surface were combined,and the synthesized nanoparticles were surface-modified by NH₂-PEG-MAL to obtain Fe₃O₄/Pd with better dispersibility and biocompatibility.The characterization data of TEM,DLS,VSM and UV spectrophotometer indicate that the prepared magnetic Janus nanoparticles not only have superparamagnetism,saturation magnetization is 38 emu/g,but also characteristic of typical Pd nanosheets at 780 nm.SPR absorption peak.(2)Tumor multimodal imaging of Fe₃O₄/Pd magnetic Janus nanoparticles.Photoacoustic and magnetic resonance imaging studies of Fe₃O₄/Pd magnetic Janus nanoparticles at different concentrations showed that the transverse relaxation rates(r₂)of Fe₃O₄ and Janus Fe₃O₄/Pd were 216 mM^-1s^-1 and 141.38 mM^-1s^-1,respectively.It is indicated that the transverse relaxation rate of the particles is reduced due to the presence of Pd in the Janus nanoparticles.However,in vitro imaging studies of photoacoustics have shown that Janus nanoparticles have better photoacoustic imaging capability than Pd nanoparticlespalladium nanosheets.In vivo imaging experiments of mouse tumor models showed that Janus nanoparticles can be enriched in the tumor area of mice,and the enrichment is the largest at 4 h,and MRI and photoacoustic imaging are the best,showing that Janus nanoparticles can achieved in photoacoustic and magnetic resonance multimodal imaging in mice.(3)Application of magneto-optical hyperthermia of Fe₃O₄/Pd magnetic Janus nanoparticles.In vitro studies of photothermal,magnetic and photo-magnetic combined hyperthermia of Fe₃O₄/Pd magnetic Janus nanoparticles at different concentrations have shown that the thermal therapy of Janus nanoparticles in vitro exhibits a synergistic warming effect at 400?g mL^-1,the temperature increased by 34.5°C,which is much larger than the sum of the rising temperature of photothermal(22°C)and the rising temperature of magnetocaloric(5.1°C),and the synergistic effect of combined hyperthermia increases with the concentration of particles.The effect is more significant.In vivo tumor combined with hyperthermia experiments showed that the Janus nanoparticle group observed significant growth inhibition and tumor volume elimination on the 18th day,while the tumor volume in the hyperthermia group decreased,but still existed.indicating Fe₃O₄/Pd magnetic Janus Janus nanoparticles is a good photo-magnetic combined hyperthermia agent with good clinical application prospects.